1. Field of Invention
This invention relates to the transmission of data by the modulation of the light output of fluorescent and other arc lamps; including the visible or invisible light output of fluorescent lamps, neon lamps, mercury vapor lamps, high or low-pressure sodium lamps, or other high-intensity discharge lamps, or any metal-halide based lamps.
This invention also relates to radio communication devices, more particularly to microprocessor controlled radio communication devices operating in and around buildings.
This invention also relates to the art of transmission of data, covering a limited area, by the modulation of a low-output radio transmitter, which is powered by the light output of fluorescent or other lamps; including the visible or invisible light output of lamps. The transmitter is designed to be small, inexpensive, and easy to install.
2. Description of Prior Art
Several methods for the transmission and reception of data messages exists. Many of these have application to offices, factories, and to buildings or complexes of buildings in general. For example, low-powered radio transmission can be used to transmit and receive data messages within a building, or the optical and infrared spectrum can be used for the transceiving of data.
However, the use of radio frequencies requires licensing and coordination for their use. Given the overcrowded radio spectrum in some areas, said licensing may be nearly impossible. In addition, while radio facilitates the transmission of data, in general that data transmission is limited in bandwidth and therefore limited in the speed of transmission. Additionally, radio energy is hard to confine, and there it is not practical to limit data transmission to the confines of any one building or office within a building or office.
In contrast, infrared transmission of data has the benefit of no licensing requirement, higher available bandwidth, and ease of confinement. However, as infrared energy is not transparent to walls or other structures, the cost of installation of an independent building-wide infrared-based transmission system is extreme. That is, each office and hallway within a building must be equipped with one or more infrared transmitters in order to provide coverage to the entire building. Each infrared transmitter will require lines for it's operating power and a data line for the data that is to be transmitted, thus requiring a supporting infrastructure that is both extensive and expensive.
In addition to wireless optical transmission as examined above, several examples exist of using modulated light in conjunction with optical fibers for the transmission of data, but these do not lend themselves to application to devices that are portable or mobile within buildings or offices.
Radio communications devices typically found in the present day business environment include one and two-way radio pagers; traditional, SMR (Specialized Mobile Radio) and “trunked” two-way radios; Cellular and PCS radio-telephones; and a wide-range of other radio devices.
These devices can be operated on either privately-owned radio systems, or on systems owned and operated by an RCC (Radio Common Carrier) or CCC (Communications Common Carrier) [a “Public Carrier”]. Public Carrier systems tend to cover large service areas often including several counties, states, or more. Indeed, some Public Carriers offer services that cover the entire U.S., Europe, or the world.
Today it is common to see pagers sold over the counter at retail and wholesale stores. While the buyer typically purchases the pager out-right, the wide-area paging service of the Public Carrier is typically leased. A user commonly enters into a contract for services by the Public Carrier on a month-to-month or yearly basis.
While Public Carrier systems tend to cover large geographic areas, private systems, for reasons of licensing and the high initial cost of equipment, tend to be limited to servicing small geographic areas.
Many private systems are designed to provide coverage to pagers and radios located within just one building or a set of buildings. That is, many private radio systems are designed to limit their coverage to radios and radio users who are in or around a particular high-rise, office building, or factory (an “In-House” system).
Since the expense involved in building a private radio system that covers a large geographic area can exceed hundreds of thousands of dollars, the services that a Public Carrier provides are deemed adequate by the vast majority of large-area services users. In such services, delays of up to five minutes can be expected given the large areas served, and given that the user is typically one of thousands or millions who must share the same radio frequency.
In contrast, in In-House systems (such as those used for the day-to-day operations of a factory or high-rise business office,) such time delays are unacceptable and cannot be tolerated. Short time-delays of even one minute prohibit Public Carrier-serviced pagers from being used for many applications such as rapid notification of incoming phone calls, rapid notification of e-mail messaging, equipment status messaging, and other sophisticated In-House communications services.
Because of technical and practical limitations, most pagers are utilized for either In-House radio paging service, or for Public Carrier wide-area paging service; but not both. Indeed, there are several users who carry two pagers on their person: one for the In-House system, and one for the wide-area Public Carrier system.
What is lacking is a pager that can concurrently receive Public Carrier generated wide-area paging signaling, and locally generated In-House paging signaling, without interference; and with minimal use of the over-crowded radio spectrum.
In a similar manner, cellular telephones lack the ability to operate on private In-House systems. Because of technical problems such as co-channel interference, cellular radio-telephones typically operate only on one of two Public Carrier cellular systems in any one geographical area.
Co-channel interference is especially a problem on radio control-channels utilized for the transmission of cellular system control data. Any radio interference on the control channel will cause the system to loose control of the radio device, and therefore incomplete or improper operation of the transmitting device may occur. Because private In-House systems will necessarily operate in close proximity to each other, co-channel interference and other types of harmful interference will likely occur. Therefore, private In-House systems thus far have not been granted licensing by the FCC.
Public Carrier cellular system fees are prohibitively high for most private In-House applications. Yet, many Public Carrier cellular users, when inside their office, would like to use their radio-telephones as their office telephone.
What is lacking is a solution that allows cellular radio-telephones to operate on existing Public Carrier cellular services, and yet facilitate the radio-telephone's cost effective use when in range of an In-House private system.
This invention proposes to combine radio-wave communications circuitry for Public Carrier wide-area services, and optical-wave communications circuitry for local In-House services; into one communications device.
Several authors have proposed optical, radio, or mixed optical and radio systems or components that may be of interest, but fail to teach the art contained in this invention. Observe and consider the following:
Several methods for the transmission and reception of data messages exists. Many of these have application to offices, factories, and to buildings or complexes of buildings in general.
However, the use of radio frequencies generally requires licensing and coordination for their use. Given the overcrowded radio spectrum in some areas, said licensing may be nearly impossible. In addition, while radio facilitates the transmission of data, in general that data transmission is limited in bandwidth and therefore limited in the speed of transmission. Additionally, medium-to-high power radio energy is hard to confine, and therefore is not practical to limit data transmission to the confines of any one building or office within a building or office.
In contrast, low-power radio transmission of data has the benefit of no licensing requirement, higher available bandwidth, and ease of confinement. However, in the past, the cost of installation of an independent building-wide low-power radio-based transmission system was high. That is, each office and hallway within a building must be equipped with one or more low-power radio transmitters in order to provide coverage to the entire building. Each low-power radio transmitter requires lines for it's operating power and a data line for the data that is to be transmitted, thus requiring a supporting infrastructure that is both extensive and expensive.